High fidelity stereophonic sound reproduction systems for home use are becoming increasingly sophisticated. Such systems are used for music reproduction, television sound reception, and the playback of video recordings. The goal of ideal stereo reproduction is to provide a realistic illusion to the listener that the listener is in the actual concert hall or other environment depicted by the sound. To accomplish this effect of essentially a three-dimensional sound, techniques which are known as "surround sound" have been developed. These techniques utilize additional speakers at the rear of the room to supply delayed sound (comparable to symphone hall reflections) to place the delayed sound in the air around the listener. The effect is that the lestener is in the same body of air as the performers, or, essentially, that of actually being in the concert hall. This is contrasted with a simple two speaker stereo system, in which all of the sound is directed to the listener from the same frontal direction as the direct sound produced by the orchestra, singer, or other musicians.
Various techniques are employed to produce "surround sound" effects in theaters and in home music systems. Even with sophisticated systems, however, there is an ideal position or "sweet spot" in the room where the balance of the left and right stereophonic sounds is directed. If the primary listener moves to some other spot in the room, it is necessary to manually adjust the balance of the left and right speakers to move the "sweet spot" to the desired position.
The Anderson U.S, Pat. No. 2,392,218 is directed to a specific system for automatically compensating for variations in background noise in the room in which an audio system is being operated. In the system of Anderson, a microphone and a speaker are mounted in the same housing The microphone is separate from the speaker, and is present for the purpose of detecting background noise in the room, and supplying a signal to adjust the output level of the speakers accordingly. The speaker level is adjusted upwardly when the level of loud background noise increases; and it is adjusted downwardly when background noise is at a minimum. The microphones and speakers in this system are totally separate components.
Systems also have been developed for receiving multiple inputs from different locations in a large room, and combining those inputs together for a signal which is reproduced over a loudspeaker. Such a system is disclosed in the Flanagan U. S. Pat. No. 4,485,484. In this system, microphones are directed to receive signals from a particular segment or location in a large room for reproduction over the loudspeaker system.
Other systems have been developed for operating various devices, such as switches, computers and the like, from spoken commands. Three patents disclosing such systems are the patents to Kishi U.S. Pat. No. 4,506,377; Noso U.S. Pat. No. 4,558,489; and Schneider U.S. Pat. No. 4,856,072. These patents all disclose systems which respond to voice or spoken instructions to operate switches of various types. Computer systems have been developed for storing a vocabulary of voiced synthesized sounds from a particular operator; so that the computer recognizes speech from that operator, and effects the desired control established by the program in the computer. For example, some limited development has taken place for utilization of such a system in a simple word processor, where the user simply speaks the material to be reproduced to the computer along with suitable commands, to produce a printed copy of the spoken dictation.
It is desirable to provide an interactive audio control system, which is capable of steering or moving the sweet spot of the reproduced sound, and further, which employs transceivers for both reproducing sound from the system and for receiving commands for effecting various operations through the system, both directly through the system.